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1 June 2011 Fluorescence/depolarization lidar for mid-range stand-off detection of biological agents
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LIDAR system for real-time standoff detection of bio-agents is presented and preliminary experimental results are discussed. The detection approach is based on two independent physical phenomena: (1) laser induced fluorescence (LIF), (2) depolarization resulting from elastic scattering on non-spherical particles. The device includes three laser sources, two receiving telescopes, depolarization component and spectral signature analyzing spectrograph. It was designed to provide the stand-off detection capability at ranges from 200 m up to several kilometers. The system as a whole forms a mobile platform for vehicle or building installation. Additionally, it's combined with a scanning mechanics and advanced software, which enable to conduct the semi-automatic monitoring of a specified space sector. For fluorescence excitation, 3-rd (355 nm) and 4-th (266 nm) harmonics of Nd:YAG pulsed lasers are used. They emit short (~6 ns) pulses with the repetition rate of 20 Hz. Collecting optics for fluorescence echo detection and spectral content analysis includes 25 mm diameter f/4 Newton telescope, Czerny Turner spectrograph and 32-channel PMT. Depending on the grating applied, the spectral resolution from 20 nm up to 3 nm per channel can be achieved. The system is also equipped with an eye-safe (1.5 μm) Nd:YAG OPO laser for elastic backscattering/depolarization detection. The optical echo signal is collected by Cassegrain telescope with aperture diameter of 12.5 mm. Depolarization detection component based on polarizing beam-splitter serves as the stand-off particle-shape analyzer, which is very valuable in case of non-spherical bio-aerosols sensing.
© (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Z. Mierczyk, K. Kopczyński, M. Zygmunt, J. Wojtanowski, J. Młynczak, A. Gawlikowski, A. Młodzianko, W. Piotrowski, A. Gietka, P. Knysak, T. Drozd, M. Muzal, M. Kaszczuk, R. Ostrowski, and M. Jakubaszek "Fluorescence/depolarization lidar for mid-range stand-off detection of biological agents", Proc. SPIE 8037, Laser Radar Technology and Applications XVI, 80371J (1 June 2011);

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